Yes, it is a nice convenience to watch a friend or relative's aircraft in the air. I also like the airport monitors (at http://www.passur.com) that show the flights around the major airports, in my case LAX.

Me also like fight tracking. But unfortunately there seems to be no flight tracking program for Europe. As I am living in Germany for me it would be more interesting to track a flight from AMS to ATH or something like that instead tracking flights within the U.S or between Europe and U.S.

Tracking flights is always fun!
If you want a good website, try Flightarrivals.com. You get specific flights from almost all the airports in the US and also international destinations. You can also see specific flights if you like. The site is really top notch!

Does anyone else use the AirNav program? I downloaded it several months ago to track friends/relatives trips to Europe etc. and now I'm addicted to it. Does anyone else know of the program and how accurate it is?

Do you think if you are tracking a flight and the plane crashes would say so?

I don't know of a single flight tracker which would actually tell you if the plane crashes. In fact, after the FedEx 727 crashed last year in Florida, FBOWEB said the plane had "landed". Flight explorer would probably just "age out" the flight, but there can be many more reasons a plane would age out besides crashing, like lost radar contact, etc.

I've gotten caught into the flight tracking addiction as well. I've used Flight Explorer Personal a couple times. I don't think it's as nice as AirNav but it's a reasonable $9.95/month for 10 hours (can't leave it on).

Without having to pay for anything my other favorite link is Flytecomm. I love this one because you can look at all the airline arrivals for a specific airport for within 24 hours. Flightarrivals.com is good too but they limit you to very small time frames.

There are two limitations that are hard to accept with flight trackers, however. First, is that they only show aircraft over the US & Canada (or at least reporting to the US/Canada). The other thing is that the data for the flights is delayed 5 minutes from real-time for security purposes (makes sense, and it wont change).

I use AirNav Live Flight Tracker. Althought you are limited to 60 hours per month usage that's much more than the 10 hours other companies offer. And the cost is the same. They have also an unlimited usage solution available. Check their homepage at http://www.airnavsystems.com for more info.

As I'm currenty living outside the US, I use AirNav ACARS Decoder + AirNav Suite 4 which makes the tracking of flights possible outside the US.